html, body {
  margin: 0;
  padding: 0;
}

body {
  background: #656a42 url(../img/background.jpg) no-repeat center top;
}

#airborne_tile {
  margin: 50px auto 0px auto;
  background: url(../img/airborne_tile.png) no-repeat left top;
  width: 608px;
  height: 728px;
  position fixed;
}

.btn a,
.btn a img {
  display: inline;
  width: 100%;
  height: 100%;
  border: none;
}

.btn {
  position: relative;
}



#btn_participate,
#btn_tosite {
  left: 155px;
  width: 284px;
  height: 46px;
}

#btn_participate {
  top: 424px;
}

#btn_tosite {
  top: 429px;
}


#btn_who,
#btn_what,
#btn_where,
#btn_how {
  left: 155px;
  width: 284px;
  height: 24px;
}

#btn_who {
  top: 461px;
}

#btn_what {
  top: 466px;
}

#btn_where {
  top: 471px;
}

#btn_how {
  top: 476px;
}